1. Field of the Invention
The present invention relates to a cutting tool, such as a circular saw and a cutter, and more particularly, to a technique for improving the workability of the cutting tool when an auxiliary device, such as a parallel guide, is attached to the circular saw.
2. Description of the Related Art
Japanese laid-open patent publication No. 2001-315101 discloses a technique for improving the workability of a circular saw for edge-cutting operation. Specifically, a guide arm is provided that can project laterally outward from the base. The distance between the circular saw and the wall can be appropriately adjusted by changing the amount of projection of the guide arm. Thus, even when using a blade with different thickness, damage to the wall can be effectively prevented.
According to the known art, the distance between the circular saw and the wall can be adjusted by the guide arm for performing an edge-cutting operation. For this edge-cutting operation, the base is formed to have a shorter width on the blade projection side in order to provide enough space for allowing projection of the blade from the side of the base. Therefore, when the edge-cutting operation is not performed, a so-called sub-base can be removably attached to the base in order to make up for the shorter width of the base. Thus, not only the base having a shorter width but the sub-base can be placed in sliding contact with the workpiece, so that the cutting operation can be performed with stability. In addition to such construction, in which the circular saw can be placed on the workpiece in sliding contact with stability, for the circular saws that can perform edge-cutting operation as well, it is further desired to improve its workability by making additional provision for properly guiding the direction of cutting the workpiece with the blade.
Moreover, Japanese laid-open patent publication No. 2001-287202 discloses a portable circular saw in which the cutting start position of the blade is kept fixed even with a change of the tilting angle of the blade. With this technique, the cutting start position of the tilted blade is kept fixed, so that the usability of the circular saw in the edge cutting operation can be improved.
According to this known art, the circular saw has a blade and a driving motor for driving the blade. The blade projects laterally outward from the side of the base when the relatively large-sized body tilts. In an actual work area of edge cutting operation, however, the space for the cutting operation using a circular saw is often limited. It is therefore desired to provide a circular saw which dose not interfere with the cutting operation even in a limited working space.